More than half of the female population colors their hair. Hair color is used most frequently when individuals age and wish to hide the gray hair that develops as a result of aging. There are generally three types of hair color: permanent, semi-permanent, or temporary. The term “permanent” generally refers to oxidative hair color that bleaches the melanin found in the hair shaft as well as imparting color. The activated peroxide in the oxidative dye composition provides a bleaching effect while the oxidative dye molecules penetrate the hair shaft and polymerize therein. While hair that is oxidatively colored provides a certain permanence, re-coloring every four to six weeks may be necessary due to new hair growth. Oxidative hair color is sold in the form of a two component kit. The reactivity of the oxidative dye and the oxidizing agent means that the two ingredients cannot be formulated into a single composition. Rather, the preferred kits have one container filled with an aqueous composition in the liquid, gel, or creme form that contains the oxidative dyes and a second container filled with a developer composition that contains an oxidizing agent, usually hydrogen peroxide The two containers are combined immediately prior to use and applied to hair. The oxidizing agent and dyes react when mixed. The mixture is applied to hair for an appropriate period of time, generally 20 to 60 minutes, then rinsed off with water. Permanent hair color is very versatile and long lasting in the colors and effects it provides, and it is only with permanent hair color that one can color hair to a shade that is lighter than the natural color
Semi-permanent hair color generally provides more lasting color than temporary dyes but without the permanence and commitment of oxidative color. Semi-permanent color is a single component product. Many of such products contain two types of dyes: one of smaller molecular size (such as nitrophenylene diamines and nitroaminophenols) that are capable of penetrating the hair shaft and being retained within. While smaller molecular size permits these dyes to more easily penetrate the hair shaft, this also makes such dyes more vulnerable to washout. The second type of dye used in semi-permanent hair color has a larger molecular size and is too large to penetrate the hair shaft of normal virgin hair. However, such larger dye molecules easily penetrate porous and damaged hair where they are preferentially retained due to their larger size. Accordingly, the balancing of the small and large dye molecules found in many semi-permanent products provides color with a uniform and durable effect Semi-permanent color provides excellent gray blending and good color retention. One big drawback of semi-permanent color is that one cannot color the hair a lighter shade than the starting color. Accordingly, semi-permanent hair color is not an option for dark haired individuals desiring to go blonde.
Temporary hair color is often found in the rinse form, and typically lasts for one shampoo. Such hair color is often used when special effects (such as green hair on St. Patrick's day) is desired. Temporary color simply coats the hair shaft with colorants that are too large to penetrate its outer surface. Minor penetration of the hair shaft may occur in individuals with damaged or porous hair, but such color application rarely lasts through more than one or two shampoos.
While oxidative, or permanent, hair color generally lasts from four to six weeks, within two to three weeks after the oxidative procedure it is common to have color fading in certain areas. In addition, since hair grows about ½ inch a month, new hair growth at the roots becomes evident after only a few weeks. In such cases, it is too early and inconvenient to undertake the oxidative dyeing process again, or to treat only the faded hairs or new hair growth in a new oxidative procedure. 
Accordingly, there is a need for a hair color product that enables consumers to touch up hair between permanent hair color procedures with a color that restores color to faded hair and new hair growth. Ideally this composition is in a single use container (no mixing of compositions prior to use required) and will not stain the scalp or surrounding skin. While the desired colorant will not provide permanent coloration, it will be an effective hair colorant for blending in gray and coloring new hair growth. In particular, such composition should provide better wear (increased fade resistance, reduced wash out), and will deposit more dye on the hair (color deposit) when compared to standard compositions. Most desirably, the composition should color the hair in a reduced period of time, say less than about twelve to fifteen, preferably about 10 minutes or less. Such a composition will wash out after a certain number of shampoos enabling use as often as needed without concern for damage to the hair. Because this composition is in a single container it may be used when desired and stored until the container is used up. It eliminates waste.
It is an object of the invention to provide a hair color composition that touch up product that can be used by the consumer as an adjunct to standard hair color to treat hairs that have faded or discolored, or to treat new hair growth, between normal oxidative coloring of the hair.
It is a further object of the invention to provide a hair color composition that optimizes the effects and longevity of hair colored with oxidative hair dye.
It is another object of the invention to provide a hair color composition that has increased fade resistance and reduced wash out when compared to standard hair colorant compositions.
It is a further object of the invention to provide a hair color composition that deposits more color on the hair.
It is a further object of the invention to provide a hair color composition that will color hair in less than about twenty, preferably less than about twelve to fifteen, most preferably about ten, minutes.
It is a further object of the invention to provide a hair color composition that exhibits reduced staining of scalp and surrounding skin.
It is another object of the invention to provide a non-oxidative hair color composition that provides improved wear and fade resistance.
It is another object of the invention to provide a hair color composition that can be applied to dry hair to touch up faded or discolored hair strands that have been previously treated with oxidative dyes, or color new hair growth, between oxidative dyeing procedures.